Biomedical subjects

P M Bemiller

Publications and source records attributed to P M Bemiller.

5 recordsLinked to original sources

PubMed1985

Effect of lead on fibroblasts taken from an 84-year-old donor.

Human, diploid fibroblasts from an 84-year-old donor (AlPos) were used to study the effect of 20, 40 and 80 micrograms/100 ml concentrations of lead on in vitro senescence. The results showed that there was a significant decrease in the number of total population doublings due to the treatment with lead. However, there was no significant difference between the effects of the three concentrations of lead. As far as nucleolar number is concerned in the case of the controls as well as in the lead-treated cells the number remained constant with aging in vitro. When the areas and dry mass of cells, nuclei and nucleoli were examined in controls and lead-treated groups at early and late doublings the results showed that in general no significant changes were noted with the exception of the 40 micrograms/100 ml lead treatment which caused a significant increase in these parameters with aging in vitro. The results are discussed and compared to those from a previous study [17] in which embryonic, IMR-90 cells were treated in a similar way. It is concluded that the fibroblasts from the 84-year-old donor AlPos are even more vulnerable than the embryonic cells to the effects of lead as indicated by the drastic curtailment of the in vitro lifespan exhibited in the case of treatment even with the lowest concentration of lead.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1981

Determination of the nuclear RNA content of cells from donors of three different ages during in vitro senescence.

Diploid fibroblasts from male donors aged 8, 40 and 84 years were grown in vitro and their nuclear RNA content was determined at early and late doublings by absorption cytophotometry after staining with Azure B for 2 hours at 40 degree C and pH 4. It was found that the average nuclear RNA content of the early doublings was lower than that of the last doubling in all three strains. This difference became smaller as donor age increased. Also, as the age of the donor increased the percentage of early passage cells with a relative nuclear RNA content of less than 6 arbitrary units decreased, those with a relative nuclear RNA content of more than 6 units increased and the diversity in nuclear RNA content increased. The distribution pattern of relative RNA content for late passage cells was similar for the three donors.

Adult↗

PubMed1979

Cytological changes senescing WI-38 cells: a statistical analysis.

Changes in the cell, nuclear, nucleolar dry masses and areas were monitored simultaneously during in vitro senescence of WI-38 human fetal lung fibroblast cells, and the results were analyzed statistically. There was a two-step increase in all six parameters studied, following an initial decrease. The patterns of increase were strikingly similar for all six measures, i.e., an initial lag period was followed by a sharp increase, a plateau and a final, abrupt increase. In all cases, there was a strong correlation between corresponding area and dry mass measurements for each cell component. The dry mass/area ratio also increased as a function of in vitro aging and ultimately doubled in value. Weak intrapassage correlations between cell, nuclear and nucleolar dry masses indicated that there were passage to passage differences in the relative rates of dry mass increases which were not apparent over long periods of growth. The increases in all muclear and nucleolar areas were interdependent until the last doubling where they increased independently. The standard deviation for all six parameters increased as a function of in vitro senescence indicating that there was an increase in the heterogeneity of cells relative to these parameters.

Cell Division↗

PubMed1978

Nucleolar changes in senescing WI-38 cells.

Changes in the area, dry mass and morphology of nucleoli were studied during in vitro aging of WI-38 cells. Interferometric methods were used for nucleolar dry mass determinations. The results show that there is (1) an increase in the fraction of cells with one large nucleolus per nucleus, 17% at population doubling 27.3 vs. 93% at population doubling 41.2, (2) an increase in mean nucleolar dry mass (583% at the last doubling), and (3) an increase in mean nucleolar area (236% at the last doubling) with in vitro senescence of WI-38 fibroblast cells. A strong correlation (r = 0.92) between nucleolar dry mass and nucleolar area was demonstrated.

Cell Division↗

PubMed1978

Nuclear area changes in senescing human diploid fibroblasts.

The pattern of mean nuclear area changes was determined in human fibroblast cell strains from male donors of three different ages (8,40 and 84 years) during their in vitro lifespan. There was a statistically significant increase in mean nuclear area of cells of all three strains during their aging in vitro. A gradual increase of the subpopulation of cells with larger nuclei was also observed. Evidence for a positive correlation between aging in vitro, as reflected by mean nuclear areas at the tenth doubling from the end of in vitro doubling activity, and donor age is presented.

Adult↗